Chemical mechanical planarization tools, and related pads for chemical mechanical planarization tools

ABSTRACT

A pad for chemical mechanical planarization comprises a material having a major surface, and asperities extending from the major surface, a ratio between a length and a width of each of the asperities greater than about 2:1, and an included angle between a leading surface of at least some asperities and the major surface greater than about 90°. Related pads, tools for chemical mechanical planarization, and related methods are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.16/265,311, filed Feb. 1, 2019, the disclosure of which is herebyincorporated herein in its entirety by this reference.

TECHNICAL FIELD

Embodiments disclosed herein relate to pads for chemical mechanicalplanarization, to tools including the pads, and to related methods. Moreparticularly, embodiments of the disclosure relate to pads for chemicalmechanical planarization, the pads including asperities extending from amajor surface thereof and shaped and configured to planarize surfaces ofa wafer by one or both of a shearing action and a rubbing action.Embodiments of the disclosure are also directed to related toolsincluding the pads, and related methods.

BACKGROUND

Fabrication of semiconductor devices, memory cells, and electronicsystems includes patterning of various features, such as conductivelines, transistors, electrodes, conductive contacts (e.g., conductiveplugs), and other features. At various stages during the fabricationprocess, materials may be deposited on the semiconductor device (e.g.,the wafer) being fabricated. Patterning of such material may includeremoval of excess materials from surfaces of the semiconductor device.In some instances, surfaces of the semiconductor device are planarizedto form a uniform surface to ensure alignment of features andmaintenance of critical dimensions during further processing acts.

Chemical mechanical planarization, which may also be characterized aschemical mechanical polishing (CMP), is a technique used to planarize,polish, or clean workpieces, such as semiconductor devices, duringfabrication thereof. In a conventional CMP process, a rotatable wafercarrier, or polishing head, is mounted on a carrier assembly. The wafercarrier head holds the wafer and positions the wafer in contact with apolishing layer of a polishing pad that is mounted on a rotatable table,which may be characterized as a platen, of a CMP tool. The polishing padincludes a microstructure of pores and randomly oriented asperities thatfacilitate removal of material from the wafer. The carrier assemblyprovides a normal force in the form of a controllable, applied pressurebetween the wafer and polishing pad. A fluid, which may comprise aslurry or other flowable medium, is dispensed onto the polishing pad andis drawn into a narrow gap between the wafer and the polishing layerwhile the polishing pad and wafer are moved relative to one another.Materials removed from the wafer are removed from between the wafer andthe polishing pad through channels (also referred to as microchannels orgrooves) in the polishing pad.

As the polishing pad moves relative to the wafer, the wafer follows atypically annular polishing track, wherein the wafer's surface directlycontacts the polishing layer of the polishing pad. The surface of thewafer is polished and planarized by chemical and mechanical action ofthe polishing pad and the fluid medium on the surface of the wafer.

Over time, the surface of the polishing pad wears, smoothing themicrostructure of the porous polishing pad structure, a process referredto in the art as “glazing.” In addition, debris removed from the wafersurface during the CMP process may clog surface voids and microchannelsof the polishing pad through which the fluid medium flows. The cloggedsurface voids and microchannels reduces the polishing rate of the CMPprocess and may result in non-uniform polishing between wafers (wafer towafer non-uniformity (WTWNU)) and between different portions of a singlewafer (within wafer non-uniformity (WIWNU)). Due to the adverse effectsof glazing and clogging of surface voids, conventional polishing padsrequire periodic surface conditioning (also referred to as “dressing”)to maintain a surface suitable for polishing the wafer. Conditioning thepolishing pad includes contacting the surfaces of the polishing pad witha conditioning disk including impregnated abrasive particles, such asdiamond particles. Although conditioning the polishing pad may create anew polishing surface, the new polishing surface may not exhibit auniform distribution of pores or surface topography and may exhibitirregular removal rates, reducing a planarity of the polished wafer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified schematic view of a tool for chemical mechanicalplanarization, in accordance with embodiments of the disclosure;

FIG. 2A is a simplified top down view of a pad for use in a chemicalmechanical planarization tool, in accordance with embodiments of thedisclosure;

FIG. 2B is a simplified enlarged view of box B illustrated in FIG. 2A;

FIG. 2C is a simplified cross-sectional view of the pad taken alongsection line C-C in FIG. 2A, in accordance with embodiments of thedisclosure;

FIG. 2D is a simplified cross-sectional view of a pad, in accordancewith other embodiments of the disclosure;

FIG. 2E is a simplified cross-sectional view of a pad includingasperities having a relief angle, in accordance with some embodiments ofthe disclosure;

FIG. 2F is a simplified cross-sectional view of a pad, in accordancewith embodiments of the disclosure;

FIG. 2G is a simplified cross-sectional view of a pad, in accordancewith embodiments of the disclosure;

FIG. 2H is a simplified cross-sectional view of a pad, in accordancewith embodiments of the disclosure;

FIG. 3 is a simplified top view of a pad having grooves, in accordancewith embodiments of the disclosure;

FIG. 4 is a simplified top view of a pad having grooves, in accordancewith other embodiments of the disclosure;

FIG. 5 is a simplified top view of another pad having grooves, inaccordance with embodiments of the disclosure; and

FIG. 6 is a simplified top view of a pad having grooves, in accordancewith yet other embodiments of the disclosure.

DETAILED DESCRIPTION

The illustrations included herewith are not meant to be actual views ofany particular chemical mechanical planarization tools or pads, but aremerely idealized representations that are employed to describeembodiments herein. Elements and features common between figures mayretain the same numerical designation except that, for ease of followingthe description, for the most part, reference numerals begin with thenumber of the drawing on which the elements are introduced or most fullydescribed.

The following description provides specific details, such as materialtypes, material thicknesses, and processing conditions in order toprovide a thorough description of embodiments described herein. However,a person of ordinary skill in the art will understand that theembodiments disclosed herein may be practiced without employing thesespecific details. Indeed, the embodiments may be practiced inconjunction with conventional fabrication techniques employed in thesemiconductor industry. In addition, the description provided hereindoes not form a complete description of a chemical mechanicalplanarization (CMP) tool, a pad for such a CMP tool, or a completedescription of a process flow for fabricating such CMP tools or pads.Only those process acts and structures necessary to understand theembodiments described herein are described in detail below. Additionalacts to form a complete CMP tool or pad, may be performed byconventional techniques.

As used herein, the terms “chemical mechanical planarization” and“chemical mechanical polishing” are used interchangeably.

As used herein, the terms “longitudinal,” “vertical,” “lateral,” and“horizontal” are in reference to a major plane of a substrate (e.g.,base material, base structure, base construction) in or on which one ormore structures and/or features are formed and are not necessarilydefined by Earth's gravitational field. A “lateral” or “horizontal”direction is a direction that is substantially parallel to the majorplane of the substrate, while a “longitudinal” or “vertical” directionis a direction that is substantially perpendicular to the major plane ofthe substrate. The major plane of the substrate is defined by a surfaceof the substrate having a relatively large area compared to othersurfaces of the substrate.

As used herein, the term “substantially” in reference to a givenparameter, property, or condition means and includes to a degree thatone of ordinary skill in the art would understand that the givenparameter, property, or condition is met with a degree of variance, suchas within acceptable tolerances. By way of example, depending on theparticular parameter, property, or condition that is substantially met,the parameter, property, or condition may be at least 90.0 percent met,at least 95.0 percent met, at least 99.0 percent met, at least 99.9percent met, or even 100.0 percent met.

As used herein, “about” or “approximately” in reference to a numericalvalue for a particular parameter is inclusive of the numerical value anda degree of variance from the numerical value that one of ordinary skillin the art would understand is within acceptable tolerances for theparticular parameter. For example, “about” or “approximately” inreference to a numerical value may include additional numerical valueswithin a range of from 90.0 percent to 110.0 percent of the numericalvalue, such as within a range of from 95.0 percent to 105.0 percent ofthe numerical value, within a range of from 97.5 percent to 102.5percent of the numerical value, within a range of from 99.0 percent to101.0 percent of the numerical value, within a range of from 99.5percent to 100.5 percent of the numerical value, or within a range offrom 99.9 percent to 100.1 percent of the numerical value.

As used herein, spatially relative terms, such as “beneath,” “below,”“lower,” “bottom,” “above,” “upper,” “top,” “front,” “rear,” “left,”“right,” and the like, may be used for ease of description to describeone element's or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. Unless otherwise specified,the spatially relative terms are intended to encompass differentorientations of the materials in addition to the orientation depicted inthe figures. For example, if materials in the figures are inverted,elements described as “below” or “beneath” or “under” or “on bottom of”other elements or features would then be oriented “above” or “on top of”the other elements or features. Thus, the term “below” can encompassboth an orientation of above and below, depending on the context inwhich the term is used, which will be evident to one of ordinary skillin the art. The materials may be otherwise oriented (e.g., rotated 90degrees, inverted, flipped) and the spatially relative descriptors usedherein interpreted accordingly.

According to embodiments described herein, a chemical mechanicalplanarization tool includes a pad including asperities extending from amajor surface of the pad in a direction that is substantially transverseto a direction of the major surface. The pad may further include poreslocated between asperities of the pad. The pores may extend into themajor surface. One or more of the asperities may be oriented, shaped,and configured to planarize a wafer by a shearing action with which thepad is brought into contact. Others of the one or more asperities of thepad may be oriented, shaped, and configured to polish (e.g., rub) one ormore surfaces of the wafer in a polishing action. In some embodiments,at least some of the asperities may include an upper surface (locateddistal from a base of the respective asperity), wherein the uppersurface is oriented at an acute (less than 90°) relief angle relative tothe major surface. The asperities may have a leading surface oriented ata leading angle with respect to the major surface and a trailing surfaceoriented at a trailing angle with respect to the major surface. As usedin this context, “leading” means directionally leading in a direction ofasperity movement during rotation of the pad, whereas “trailing” meansdirectionally trailing in a direction of asperity movement duringrotation of the pad. The leading angle may be tailored to increase astiffness and, thus, durability of the asperity and to optimize contactbetween the pad and the wafer. In use and operation, the leading anglemay facilitate removal of material from a wafer by a shearing actioneffected by a shearing edge at a distal extent of the leading surface ofthe asperity.

The asperities may be oriented on the pad at a skew angle, which may bedefined as an angle between a longitudinal axis of the asperity and aradial direction of the pad at the location where the particularasperity is located. Accordingly, the pad may include asperities thatare not substantially aligned (parallel) with each other. The skew anglemay be tailored to at least one of adjust a material removal rate of thepad, to adjust the shearing action of the asperities, or to adjust astiffness of the asperities. Each of the asperity height, asperitywidth, asperity length, relief angle, skew angle, leading angle,trailing angle, asperity spacing (pitch), asperity overlap, and padthickness may be tailored to affect one or more of a length scale ofplanarization of the wafer (an effective distance over which the pad mayeffectively planarize surfaces of the wafer in use and operation), aremoval rate achieved by the pad, an amount of interaction between theupper surface of the asperities and the wafer, or a rigidity of theasperities.

Semiconductor wafers polished with the pad including the asperities,according to embodiments described herein, may exhibit improved surfaceplanarity, reduced within-wafer non-uniformity, and reduced wafer towafer non-uniformity.

FIG. 1 is a simplified schematic view of a chemical mechanicalplanarization (CMP) tool 100. The CMP tool 100 may be configured andoperated to remove material from a surface of a wafer 102 in at leastone of a planarizing or polishing operation. The wafer 102 may be heldby a carrier 104 which may be configured and operated to hold the wafer102 in place during rotation of the wafer 102. A retaining ring 106 maycircumferentially surround the wafer 102 to hold the wafer 102 in placeduring operating of the CMP tool 100. The retaining ring 106 may beconfigured to maintain the wafer 102 in a position aligned with thesurface of a pad 114. In some embodiments, the retaining ring 106 isintegral with the carrier 104. In some embodiments, a backing materialor backing pad may be located between the wafer 102 and the carrier 104.The retaining ring 106 may securely position the wafer 102 under thecarrier 104 during CMP processes. In addition, the retaining ring 106may facilitate uniform material removal, such as proximate a peripheryof the wafer 102.

The wafer 102 may comprise a number of in-process semiconductor devices,such as one or more of semiconductor devices including arrays of memorycells, logic circuits, or processor circuits, as known in the art. Thesemiconductor devices may include active and passive circuit elements aswell as other features, such as, for example, memory cells, transistors,capacitors, electrically conductive lines (e.g., word lines, digitlines, sense lines, bit lines, data lines), conductive contacts (e.g.,conductive plugs), redistribution lines, and other components ofcircuitry associated with, for example, memory or other semiconductordevices. Some of the patterns and features of the wafer 102 may have alength scale (e.g., pitch in a particular direction) falling within acertain range and other patterns and features of the wafer 102 may havea length scale (e.g., pitch in a particular direction) falling withinanother range. By way of nonlimiting example, various features of thewafer 102 may be spaced apart (e.g., separated) from each other by anedge to edge, or center to center, distance, which may be characterizedas a “pitch” within a range from about 10 nm to about 200 nm, such asfrom about 10 nm to about 20 nm, from about 20 nm to about 50 nm, fromabout 50 nm to about 100 nm, or from about 100 nm to about 200 nm. Otherfeatures of the wafer 102 may be spaced from each other by an edge toedge, or center to center, distance (e.g., a pitch), within a range fromabout 1 μm to about 100 μm, such as from about 1 μm to about 5 μm, fromabout 5 μm to about 10 μm, from about 10 μm to about 20 μm, from about20 μm to about 40 μm, from about 40 μm to about 60 μm, from about 60 μmto about 80 μm, or from about 80 μm to about 100 μm. According toembodiments described herein, the pad 114 may be used to planarizevarious portions of the wafer 102 including different featuresexhibiting a different pitch from one another.

The wafer 102 may include exposed surfaces (surfaces to be brought intocontact with the pad 114) including various compositions. For exampleand not by way of limitation, exposed surfaces of the wafer 102 mayinclude at least one of silicon, dielectric materials (e.g., silicondioxide, phosphosilicate glass, borosilicate glass, fluorosilicateglass), metal oxides (e.g., titanium oxide, hafnium oxide, zirconiumoxide, aluminum oxide, tungsten oxide, ruthenium oxide, iridium oxide),metal nitrides (e.g., tungsten nitride, titanium nitride, tantalumnitride, titanium aluminum nitride), metals (e.g., at least one oftungsten, titanium, nickel, platinum, ruthenium, rhodium, aluminum,copper, molybdenum, gold, iridium), metal silicides, metal carbides, aconductively-doped semiconductor material (e.g., conductively-dopedsilicon, conductively-doped germanium, conductively-doped silicongermanium), polysilicon, or another material.

In use and operation, the wafer 102 may be rotated relative to arotational axis 108, as indicated by arrow 110. The rotational axis 108may comprise, for example, a shaft in operable communication with adrive (e.g., motor) for rotating the carrier 104 and the wafer 102. Insome embodiments, the carrier 104 may be configured to move in thelateral direction, as indicated by arrow 112. In other words, thecarrier 104 may be configured to move in one or both of the x-directionand the y-direction.

The pad 114 may be secured to a platen 116. In some embodiments, asubpad may be located between the pad 114 and the platen 116. The platen116 may be operably coupled to a drive 118, which may be configured toimpart rotational motion to the platen 116, as indicated by arrow 120.In use and operation, one or both of the wafer 102 and the pad 114 maybe rotated with respect to the other of the wafer 102 and the pad 114 toprovide relative motion between the wafer 102 and the pad 114.

In some embodiments, the pad 114 may be rotated in a direction (e.g.,clockwise or counterclockwise) at a rate within a range from about 30rotations per minute (RPM) to about 150 RPM, such as from about 30 RPMto about 45 RPM, from about 45 RMP to about 60 RPM, from about 60 RPM toabout 75 RPM, from about 75 RPM to about 100 RPM, from about 100 RPM toabout 125 RPM, or from about 125 RPM to about 150 RPM. In someembodiments, the pad 114 is rotated at a rate within a range from about45 RPM to about 125 RPM. The wafer 102 may be rotated in a direction(e.g., clockwise or counterclockwise) at a rate within a range fromabout 30 RPM to about 150 RPM, such as from about 30 RPM to about 45RPM, from about 45 RMP to about 60 RPM, from about 60 RPM to about 75RPM, from about 75 RPM to about 100 RPM, from about 100 RPM to about 125RPM, or from about 125 RPM to about 150 RPM. In some embodiments, thewafer 102 is rotated at a rate within a range from about 45 RPM to about125 RPM. In some embodiments, the pad 114 and the wafer 102 are rotatedin the same direction. In some embodiments, the pad 114 and the wafer102 are rotated at substantially the same rate. In some suchembodiments, a relative velocity between the surface of the pad 114 andthe surface of the wafer 102 may be substantially uniform along asurface of the wafer 102. In other words, the motion of the pad 114relative to the wafer 102 may be substantially uniform across thesurface of the wafer 102. In other embodiments, the pad 114 and thewafer 102 are not rotated in the same direction. By way of nonlimitingexample, the pad 114 and the wafer 102 may be rotated in oppositedirections (e.g., clockwise and counterclockwise).

The pad 114 may comprise a polymeric material. By way of nonlimitingexample, the pad 114 may comprise a thermoplastic material such as atleast one of polypropylene, polyethylene, polycarbonate, polyurethane(e.g., a cross-linked polyurethane foam material),polytetrafluoroethylene, polyethylene tetraphthalate, polyethyleneoxide, polysulphone, polyetherketone, polyetheretherketone (PEEK), apolyimide, poly(vinylalcohol) (PVA), a nylon material, polyphenylenesulfide, polystyrene, polyoxymethylene plastic, a thermoset materialsuch as a polyurethane, epoxy resin, a phenoxy resin, a phenolic resin,a melamine resin, a polyimide, and a urea-formaldehyde resin. In someembodiment, the polishing pad 114 comprises a polymer. In someembodiments, the pad 114 comprises a polyurethane material.

In use and operation, a controlled, downward (i.e., normal) force,indicated by arrow 122, may be applied to the wafer 102 as the wafer 102is moved relative to the pad 114. A fluid medium 126 may be provided onthe polishing pad 114 via a dispenser in the form of nozzle 124 duringoperation of the CMP tool 100. The nozzle 124 may be configured to movelaterally (in the x-direction, the y-direction, or both), such asindicated by arrow 125.

The composition of the fluid medium 126 may vary depending on thematerial composition of the materials on the surface of the wafer 102and the desired properties of the wafer 102. The fluid medium 126 maycomprise at least one of water (e.g., deionized water), phosphoric acid(H₃PO₄), a peroxide, a carboxylic acid, an inorganic acid, ammonia, oneor more surfactants, one or more types of particles, and anothermaterial. The particles may comprise, for example, at least one of metaloxide particles (e.g., silica (SiO₂), ceria (CeO₂), alumina (Al₂O₃),titanium dioxide (TiO₂), zirconium oxide (ZrO), other oxide particles),silicon carbide (SiC), silicon nitride (Si₃N₄), and aluminum nitride(AlN). In other embodiments, the fluid medium 126 comprises one or morematerials suitable for chemical buffing applications. In someembodiments, the fluid medium 126 comprises one or both of silicaparticles and ceria particles. In some embodiments, the fluid medium 126comprises deionized water. In some such embodiments, the fluid medium126 may not include particles. It is notable that embodiments of pads114 of the present disclosure, by virtue of the shearing actionseffected by pad asperities, may reduce or eliminate the need forparticulate matter in the fluid medium for some operations, as isrequired by conventional polishing pads.

By way of nonlimiting example, in some embodiments, the fluid medium 126may comprise a so-called abrasive-less composition and may comprise, forexample, a wet etchant such as one or more of sulfuric acid, phosphoricacid, hydrochloric acid, hydrofluoric acid, ammonium fluoride, potassiumhydroxide, ammonium hydroxide, hydrogen peroxide, sodium hydroxide,acetic acid, and another wet etchant. The fluid medium 126 may furthercomprise one or more chelating agents. In some such embodiments, the pad114 may be used for removing metals (e.g., tungsten, titanium, nickel,platinum, ruthenium, rhodium, aluminum, copper, molybdenum, gold,iridium) from a surface by chemical mechanical planarization. Withoutbeing bound by any particular theory, it is believed that such metalsmay be removed by a combination of shearing action and chemical etching.

FIG. 2A is a top down view of the pad 114 shown in FIG. 1. The pad 114may include asperities 130 oriented on the pad 114. The asperities 130may be arranged in a pattern on the pad 114. In some embodiments, thepad 114 may include segments 114 a-114 h, which may also be referred toas “slices” in some embodiments. In some embodiments, the pad 114comprises a plurality of segments 114 a-h, each segment 114 a-114 hhaving similarly oriented and patterned asperities 130. In someembodiments, each segment 114 a-114 h may be substantially the same asthe other segments 114 a-114 h. Stated another way, if a first segment114 a is rotationally translated to overlie a second segment 114 b, thefirst segment 114 a and the second segment 114 b would be substantiallythe same with similarly oriented asperities 130. In other embodiments,the asperities 130 may be randomly oriented on the polishing pad 114. Insome embodiments, each segment 114 a-114 h has about a same number ofasperities 130 as the other segments 114 a-114 h. In yet otherembodiments, at least one of the segments 114 a-114 h may include adifferent number of asperities 130 than at least another of the segments114 a-114 g.

The pad 114 may have a diameter within a range from about 100 mm toabout 1,000 mm, such as from about 100 mm to about 250 mm, from about250 mm to about 500 mm, from about 500 mm to about 750 mm, or from about750 mm to about 1,000 mm. However, the disclosure is not so limited andthe diameter of a given pad 114 may be different than those describedabove.

As illustrated in FIG. 2A, an angle θ may be defined as an angle betweenthe x-axis and a line (radial line) extending from the center of the pad114 toward a circumference of the pad 114 in a counterclockwisedirection. For example, the angle θ may be equal to about 90° in theupward vertical direction, equal to about 180° in the left direction,and equal to about 270° in the downward direction in FIG. 2A. A tangent132 of the pad 114 may change as the angle θ changes. In use andoperation, the direction of the tangent 132 at a particular angle θ maybe representative of a direction of motion of the pad 114 as the pad 114is rotated by the drive 118 (FIG. 1). As one example, the direction ofmotion of the pad 114 in segment 114 c may be upward in the viewillustrated in FIG. 2A when the direction of motion of the pad 114 is ina counterclockwise direction in FIG. 2A.

Although FIG. 2A illustrates 8 segments 114 a-114 h, the disclosure isnot so limited. In other embodiments, the pad 114 may include less than8 segments 114 a-114 h (e.g., 4 segments, 5 segments, 6 segments, 7segments) or may include more than 8 segments 114 a-114 h (e.g., 9segments, 10 segments, 11 segments, 12 segments). In some embodiments,the pad 114 includes more than 8 segments 114 a-114 h, such as more than12 segments 114 a-114 h, more than 18 segments 114 a-114 h, more than 24segments 114 a-114 h, or more than 36 segments 114 a-114 h. As thenumber of segments 114 a-114 h increases, a relative angle betweenasperities 130 of adjacent segments 114 a-114 h may be reduced. In otherwords, as the number of segments 114 a-114 h increases, the uniformityof relative orientation of the asperities 130 proximate one another isincreased. For example, referring to FIG. 2A, asperities 130 in a firstsegment 114 a may be oriented at about 45° with respect to asperities inan adjacent second segment 114 b. By way of comparison, if the pad 114includes, for example, 16 segments 114 a-114 h, asperities 130 in thefirst segment 114 a may be oriented at an angle of about 22.5° withrespect to asperities 130 in an adjacent, second segment 114 b.

In some embodiments, a longitudinal axis 134 (FIG. 2B) of asperities 130at the same angle θ on the pad 114 may be substantially parallel. Inother words, asperities 130 at the same angular orientation θ on thepolishing pad 114 may be substantially parallel with each other. In someembodiments, asperities 130 within the same segment 114 a-114 h may besubstantially parallel with each other (e.g., have substantiallyparallel longitudinal axes 134). The relative angle between asperities130 at a first angular orientation θ₁ and asperities 130 at a secondangular orientation θ₂ may be equal to about a difference between thefirst angular orientation θ₁ and the second angular orientation θ₂(i.e., θ₁-θ₂). In other words, and only as an example, the relativeangle between a longitudinal axis of an asperity 130 located on, forexample, the x-axis, and longitudinal axis of an asperity 130 locatedon, for example, the y-axis, may be about 90°.

In some embodiments, the asperities 130 located within the same segment114 a-114 h may be substantially parallel with each other and theasperities 130 located within different segments 114 a-114 h may beoffset (angled) with respect to each other. In some embodiments, theasperities 130 in a first segment 114 a-114 h located about 180° from asecond segment 114 a-114 h may be substantially parallel with eachother. Stated another way, the asperities 130 in a pair of opposingsegments 114 a-114 h may mirror one another. In yet other embodiments,asperities 130 within the same segment 114 a-114 h may not besubstantially parallel with each other.

Accordingly, in some embodiments, the pad 114 comprises a number ofsegments 114 a-114 h. Each segment 114 a-114 h may include asperities130 and may include, for example, a same number of asperities 130 as theother segments 114 a-114 h. Each segment 114 a-114 h may includeasperities 130 that are substantially parallel with each other. Theasperities 130 of each segment 114 a-114 h may include asperities 130that are not substantially parallel (offset) with asperities 130 of atleast some adjacent segments 114 a-114 h.

In FIG. 2A, the asperities 130 are oriented such that the fluid medium126 and polishing byproducts (e.g., removed materials from the wafer102) are directed outward when the pad 114 is rotated (e.g., in acounterclockwise direction, in a clockwise direction). In otherembodiments, the asperities 130 are oriented such that the fluid medium126 and the byproducts are directed inward. In some such embodiments, aportion of the fluid medium 126 may be recycled inwardly rather thandirected to the outside of the pad 114.

A density of the asperities 130 may be within a range from about 10/cm²to about 40,000/mm², such as from about 10/cm² to about 50/cm², fromabout 50/cm² to about 1/mm², from about 1/mm² to about 100/mm², fromabout 100/mm² to about 500/mm², from about 500/mm² to about 1,000/mm²,from about 1,000/mm² to about 10,000/mm², or from about 10,000/mm² toabout 40,000/mm². In some embodiments, the density of the asperities 130may be within a range from about 10/mm² to about 500/mm², such as fromabout 10/mm² to about 25/mm², from about 25/mm² to about 50/mm², fromabout 50/mm² to about 75/mm², from about 75/mm² to about 100/mm², fromabout 100/mm² to about 200/mm², from about 200/mm² to about 300/mm²,from about 300/mm² to about 400/mm², or from about 400/mm² to about500/mm².

In some embodiments, the pad 114 includes grooves (channels) 145. Insome embodiments, the grooves 145 are located at boundaries betweenadjacent segments 114 a-114 h. The grooves 145 may facilitate flow ofthe fluid medium 126 (FIG. 1) between the wafer 102 (FIG. 1) and the pad114. In addition, the grooves 145 may facilitate flow of debris from thewafer 102 away from an interface between the pad 114 and the wafer 102.The grooves 145 may extend into a surface of the pad 114 a distancewithin a range from about 250 μm to about 750 μm, such as from about 250μm to about 500 μm, or from about 500 μm to about 750 μm, although thedisclosure is not so limited. The presence of such channels may enhancefluid dynamics between the pad 114 and the wafer 102.

FIG. 2B is a simplified expanded view of the box B of FIG. 2A. FIG. 2Billustrates some of the asperities 130 of segment 114 c. In FIG. 2B, thetangent of the pad 114 proximate the asperities 130 illustrated isrepresented by arrow 132. Accordingly, in FIG. 2B, the intendeddirection of motion of the pad 114 in use and operation is in the upwardin the view illustrated in FIG. 2B.

The asperities 130 may be oriented at a skew angle α relative to a planethat is orthogonal to the tangent 132 of the pad 114 (or the tangent ofthe pad 114 at that particular location). Stated another way, anasperity 130 may be oriented at a skew angle α defined as an anglebetween the longitudinal axis 134 of the asperity 130 and the radialdirection of the pad 114 at the location of the asperity 130. The skewangle α may also be referred to herein as a so-called “orientationangle.” The asperities 130 of each segment 114 a-114 h may be orientedat the skew angle α between the longitudinal axis 134 of the asperities130 and a line orthogonal to the tangent 132 (e.g., the radialdirection) of the particular segment 114 a-114 h in which the asperities130 are located. In some embodiments, where the individual segments 114a-114 h extend over a range of angles θ (FIG. 2A), the tangent 132 ofthe particular segment may be represented as the tangent 132 at theangular center of the particular segment 114 l-114 h. For example, thetangent 132 of the pad 114 at segment 114 c (FIG. 2A) may be determinedat an intersection of the x-axis and the circumference of the pad 114 atthe segment 114 c and the skew angle α may correspond to the anglebetween the longitudinal axis 134 of the asperity 130 and the x-axis.

It will be understood that the skew angle α of asperities 130 within thesame segment 114 a-114 h differ from the skew angle α of otherasperities 130 within the same segment 114 a-114 h since the asperities130 may be substantially parallel, even though they may be located at adifferent angular location θ on the pad 114. In other words, the skewangle α of the asperities 130 within a given section 114 a-114 h mayvary by as much as the fraction of the angular area occupied by thesegment 114 a-114 h. For example, where the pad 114 comprises eightsegments 114 a-114 h, each segment 114 a-114 h occupying about the sameportion of the pad 114, the difference in skew angle α between some ofthe asperities 130 may be as much as about 45° (i.e., 360/8=45°). Inother embodiments, the asperities 130 within the same segment 114 a-114h may be oriented at substantially the same skew angle α. In some suchembodiments, the asperities 130 within the same segment 114 a-114 h maynot be substantially parallel. In some embodiments, asperities 130within a first segment 114 a-114 h may have about the same skew angle αas asperities 130 located at a corresponding location within a secondsegment 114 a-114 h. For example, asperities 130 located proximate anangular center of a first segment 114 a-114 h may exhibit about the sameskew angle α as asperities located proximate an angular center of asecond segment 114 a-114 h. Although FIG. 2B illustrates that each ofthe asperities 130 has substantially the same skew angle α, thedisclosure is not so limited. In some embodiments, the skew angle α mayvary from asperity 130 to asperity 130. As only one example, the skewangle α may increase with an increasing distance of the asperities 130from a center of the pad 114.

As a number of segments 114 a-114 h of the pad 114 increases, avariation in the skew angle α between asperities 130 within the samesegment 114 a-114 h may be reduced.

Since the skew angle α of an asperity 130 is defined as the anglebetween the longitudinal axis 134 of the asperity 130 and a radial line(a line that is orthogonal to the tangent 132 of the pad 114) at thesame angular orientation θ as the asperity 130, the asperities 130 maybe oriented to have substantially the same skew angle α, even thoughthey are not oriented at the same angle θ (FIG. 2A) with respect to thex-axis. In other words, even though the asperities 130 are notsubstantially parallel (or the longitudinal axes 134 of the asperities130 are not substantially parallel), the asperities 130 may exhibit auniform (substantially uniform) skew angle α. In some embodiments, eventhough the asperities 130 of a first segment 114 a-114 h are notsubstantially parallel with asperities 130 of a second segment 114 a-114h, the asperities 130 of the first segment 114 a-114 h may exhibit aboutthe same skew angle α as the asperities 130 of the second segment 114a-114.

The substantially uniform skew angle α may facilitate substantiallyuniform material removal from the surfaces of the wafer 102 (FIG. 1) andmay facilitate a substantially uniform planarization of the wafer 102.In addition, the skew angle α may be tailored to adjust a distributionof forces applied between the polishing pad 114 and the wafer 102. Forexample, as the skew angle α is increased, a radial force (a force inthe radial direction) of the pad 114 may be reduced and a transverseforce (a force in a direction that is orthogonal to the radial force)may be increased.

The skew angle α may be within a range from about 0° (greater than about0°) and about 80° (e.g., less than or equal to about 80°), such as fromabout 0° and about 5°, from about 5° and about 10°, from about 10° andabout 15, from about 15° and about 30°, from about 30° and about 45°,from about 45° and about 60°, or from about 60° to about 80°. In someembodiments, the skew angle α is within a range from about 25° and about45°, such as from about 20° and about 25°, from about 25° and about 30°,from about 30° and about 35°, from about 35° and about 40°, or fromabout 40° and about 45°. In some embodiments, the skew angle α may begreater than about 45°. Without being bound by any particular theory, itis believed that an increasing skew angle α increases a shearing(cutting) action of the asperities 130 and facilitates improvedplanarization of the wafer 102 due to a reduced area (swath) covered perasperity 130 during rotation of the pad 114 relative to the wafer 102.In addition, an increasing skew angle α may facilitate an effectivelylonger asperity 130 in the direction of motion that bridges peaks intopography of the wafer 102. Bridging the peaks in topography of thewafer 102 may facilitate preferential material removal from uppersurfaces of the wafer 102 relative to lower surfaces (e.g., trenches) ofthe wafer 102 and reduce an extent of so-called “dishing.” In otherwords, as the skew angle α increases, each individual asperity 130 maycontact a smaller surface area (swath) of the wafer 102 during rotationof the wafer 102. Stated in yet another way, increasing the skew angle αmay reduce an amount by which the asperity 130 extends in the radialdimension, reducing the swath of the wafer 102 contacted by the asperity130 during use of the pad 114.

With continued reference to FIG. 2B, the asperities 130 may be orientedand patterned on the polishing pad 114 to have a radial pitch P_(R) anda transverse pitch P_(T). The radial pitch P_(R) may be defined as adistance between similar features in the radial direction. Thetransverse pitch P_(T) at a particular location may be defined as adistance between similar features in a direction that is transverse tothe radial direction at that particular location. The transversedirection at a particular location may be a direction that isperpendicular to the radial direction at the particular location.

The radial pitch P_(R) may be within a range from about 5 μm to about1,000 μm, such as from about 5.0 μm to about 10.0 μm, from about 10.0 μmto about 50 μm, from about 50 μm to about 100 μm, from about 100 μm toabout 500 μm, or from about 500 μm to about 1,000 μm. However, thedisclosure is not so limited, and the radial pitch P_(R) may bedifferent than those described above.

The transverse pitch P_(T) may be within a range from about 5 μm toabout 1,000 μm, such as from about 5.0 μm to about 10.0 μm, from about10.0 μm to about 50 μm, from about 50 μm to about 100 μm, from about 100μm to about 250 μm, or from about 250 μm to about 500 μm, or from about500 μm to about 1,000 μm. However, the disclosure is not so limited, andthe transverse pitch P_(T) may be different than those described above.In some embodiments, the transverse pitch P_(T) is equal to about theradial pitch P_(R). In other embodiments, the transverse pitch P_(T) isgreater than the radial pitch P_(R). In yet other embodiments, thetransverse pitch P_(T) is less than the radial pitch P_(R).

A ratio between the transverse pitch P_(T) and the radial pitch P_(R)may be within a range from about 0.1:1.0 to about 10.0:1.0, such as fromabout 0.1:1:0 to about 0.25:1.0, from about 0.25:1.0 to about 0.50:1.0,from about 0.75:1.0 to about 1.0:1.0, from about 2.5:1.0 to about5.0:1.0, from about 5.0:10 to about 7.5:1.0, or from about 7.5:1.0 toabout 10.0:1.0. In other words, the radial pitch P_(R) may be as much asten times greater than the transverse pitch P_(T) and the transversepitch P_(T) may be as much as ten times greater than the radial pitchP_(R).

The length L of the asperities 130, which may be in a direction that isparallel with the direction of the longitudinal axis 134 (FIG. 2B) ofthe respective asperity 130, may be within a range from about 50 μm toabout 1,000 mm, such as from about 50 μm to about 75 μm, from about 75μm to about 100 μm, from about 100 μm to about 200 μm, from about 200 μmto about 400 μm, from about 400 μm to about 600 μm, from about 600 μm toabout 800 μm, or from about 800 μm to about 1,000 μm. In someembodiments, the length is within a range from about 100 μm to about 500μm, such as from about 100 μm to about 200 μm, from about 200 μm toabout 300 μm, from about 300 μm to about 400 μm, or from about 400 μm toabout 500 μm. Without being bound by any particular theory, it isbelieved that tailoring the length L may facilitate bridging wafertopography having a certain length scale (e.g., pitch between adjacentfeatures). A greater length may increase the length scale and may reducea stiffness of the asperity 130.

A width W of an upper surface 140 (FIG. 2C) of the asperities 130 may bewithin a range from about 10 μm to about 200 μm, such as from about 10μm to about 25 μm, from about 25 μm to about 50 μm, from about 50 μm toabout 75 μm, from about 75 μm to about 100 μm, from about 100 μm toabout 150 μm, or from about 150 μm to about 200 μm. In some embodiments,the width W is within a range from about 20 μm to about 100 μm. Anincreasing width W may increase a stiffness of the asperity 130 and mayalso increase a length scale of planarization of the polishing pad 114.The width W may be in a direction that is substantially perpendicular tothe length L and the longitudinal axis 134 of the asperity 130.

An aspect ratio of the asperities 130, defined as a ratio between thelength L and the width W, may be within a range from about 2:1 to about20:1, such as from about 2:1 to about 3:1, from about 3:1 to about 4:1,from about 4:1 to about 5:1, from about 5:1 to about 10:1, from about10:1 to about 15:1, or from about 15:1 to about 20:1. In other words,the length L of the asperities 130 may be at least about 2 times, atleast about 3 times, at least about 4 times, at least about 5 times, atleast about 10 times, at least about 15 times, or even at least about 20times greater than the width W of the asperities 130. In someembodiments, the aspect ratio of the asperities 130 is within a rangefrom about 2:1 to about 5:1 or from about 3:1 to about 5:1. In otherembodiments, the aspect ratio is greater than about 5:1.

In some embodiments, a degree of overlap of the asperities 130, whichmay be represented as radial distance D_(R), may be within a range fromabout 0.5 μm to about 500 μm, such as from about 0.5 μm and about 1.0μm, from about 1.0 μm to about 5 μm, from about 5 μm to about 10 μm,from about 10 μm to about 50 μm, from about 50 μm to about 100 μm, fromabout 100 μm to about 200 μm, from about 220 μm to about 300 μm, fromabout 300 μm to about 400 μm, or from about 400 μm to about 500 μm. Insome embodiments, the asperities 130 may overlap one another by a radialdistance D_(R) that is within a range from about 0% to about 50% thelength L of the asperities 130, such as from about 0% to about 10%, fromabout 10% to about 20%, from about 20% to about 30%, from about 30% toabout 40%, or from about 40% to about 50% the length L of the asperities130.

Increasing the degree of overlap of the asperities 130 may facilitateimproved planarization of features on the wafer 102 having a relativelygreater pitch without increasing a length L of the asperities 130 due tooverlap of the paths of adjacent asperities 130, providing a redundantshearing action across the surface of the wafer 102. In someembodiments, the degree of overlap of the asperities 130, the transversepitch P_(T), and the radial pitch P_(R) may affect a localized pressureand a number of contact areas between the pad 114 and the wafer 102,which may affect removal rates, planarization, and the hydrodynamics ofthe fluid medium 126 (FIG. 1) in use and operation.

FIG. 2C is a simplified cross-sectional view of the pad 114 adjacent tothe wafer 102, taken along section line C-C of FIG. 2A. In FIG. 2C, thewafer 102 is moving from right to left relative to the pad 114, asindicated at arrow 103. The pad 114 may include the asperities 130 andmay further include one or more pores 136 located between adjacentasperities 130.

In some embodiments, a subpad 150 may be located adjacent (e.g., below)the pad 114. The subpad 150 may be bonded to the pad 114 with, forexample, an adhesive. The subpad 150 may be located between the pad 114and the platen 116 (FIG. 1). The subpad 150 may improve uniformity ofplanarity across the surface of the wafer 102. In some embodiments, thesubpad 150 may comprise a material of substantially greater rigiditythan material of pad 114, which may be of much lesser thickness. In somesuch embodiments, the pad 114 may be less prone to deformation in useand operation. In other embodiments, the subpad 150 comprises a softmaterial exhibiting conforming properties. In some such embodiments, thepad 114 may be configured to conform to surfaces of the wafer 102(FIG. 1) in use and operation.

A combined thickness T of the pad 114 and the subpad 150 may be within arange from about 0.5 mm to about 5.0 mm, such as from about 0.5 mm toabout 1.0 mm, from about 1.0 mm to about 2.0 mm, from about 2.0 mm toabout 3.0 mm, from about 3.0 mm to about 4.0 mm, or from about 4.0 mm toabout 5.0 mm. In some embodiments, the thickness T is within a rangefrom about 2.5 mm to about 3.0 mm. The thickness T and the hardness ofthe pad 114 and subpad 150 may affect a degree of conformability of thepad 114 to the wafer 102 (FIG. 1). By way of nonlimiting example, as thethickness T is increased, a relatively soft pad 114 may be configured tomore substantially conform to surface features of the wafer 102.

With continued reference to FIG. 2C, the asperities 130 may extend froma major surface 138 of the pad 114, which may also be referred to as aland region of the pad 114, by a height H. The major surface 138 may belocated between the asperities 130 and the pores 136. In someembodiments, the major surface 138 is substantially planar and the majorsurface 138 between a first set of asperities 130 is coplanar with themajor surface 138 between another set of asperities 130.

The pores 136 may exhibit any shape such as, for example, at least oneof cylindrical, spherical (truncated spherical), cubic, rectangularprism, triangular prism, hexagonal prism, triangular pyramid, 4, 5, or6-sided pyramid, truncated pyramid, cone, truncated cone, or anothershape. In some embodiments, the pores 136 exhibit the same shape. Inother embodiments, at least some of the pores 136 have different shapesthan at least others of the pores 136.

The pores 136 may have a depth D that is less than about 1 mm, less thanabout 500 μm, less than about 250 μm, less than about 100 μm, or evenless than about 50 μm. The pores 136 may have a dimension (e.g.,diameter) at a location substantially coplanar with the major surface138 within a range from about 10 μm to about 10 mm, such as from about10 μm to about 20 μm, from about 20 μm to about 40 μm, from about 40 μmto about 60 μm, from about 60 μm to about 80 μm, from about 80 μm toabout 100 μm, from about 100 μm to about 250 μm, from about 250 μm toabout 500 μm, or from about 500 μm to about 1 mm. In some embodiments,the dimension (the mean pore dimension) may be about 20 μm.

The height H of the asperities 130 may be within a range from about 5 μmto about 200 μm, such as from about 5 μm to about 10 μm, from about 10μm to about 25 μm, from about 25 μm to about 50 μm, from about 50 μm toabout 100 μm, from about 100 μm to about 150 μm, of from about 150 μm toabout 200 μm. In some embodiments, the height H is within a range fromabout 10 μm to about 40 μm. A shorter height H may increase a stiffnessof the asperity 130. In some embodiments, the height H of an asperity130 may not be substantially uniform. In other words, a distance betweenthe upper surface 140 of the asperity 130 and the major surface 138 ofthe pad 114 may vary within the particular asperity 130.

With continued reference to FIG. 2C, the asperities 130 may have aleading surface 142 and a trailing surface 144. The leading surface 142may terminate at a shearing edge or a shearing (cutting) edge 146 at adistal extent of the leading surface 142. At least a portion of theleading surface 142 may be oriented and configured to engage and shear(cut) material from a portion of the wafer 102 at the shearing edge 146as the asperity 130 passes proximate the wafer 102.

The leading surface 142 may be oriented at a leading surface includedangle θ_(LS) with respect to the major surface 138. The leading surfaceincluded angle θ_(LS) may be within a range from about 45° to about150°, such as from about 45° to about 60°, from about 60° and about 75°,from about 75° and about 90°, from about 90° to about 105°, from about105° to about 120°, from about 120° to about 135°, or from about 135° toabout 150°. In some embodiments, the leading surface included angleθ_(LS) may be within a range from about 90° (e.g., greater than about90°) and about 135°, such as from about 90° to about 120°. In someembodiments, the leading surface included angle θ_(LS) is greater thanabout 90°.

In some embodiments, the leading surface 142 may form a so-calledleading surface rake angle θ_(RLS) with the major surface 138. Theleading surface rake angle θ_(RLS) may be defined as an angle between aline normal to a major surface 138 of the wafer 102 and the leadingsurface 142. The leading surface rake angle θ_(RLS) may be within arange from about 0° to about 45°, such as from about 0° to about 15°,from about 15° to about 30°, or from about 30° to about 45°. In someembodiments, the leading surface rake angle θ_(RLS) may be within arange from about 0° to about 30°. The leading surface rake angle θ_(RLS)may also be referred to herein as a leading surface draft angle orleading surface back rake angle.

The trailing surface 144 may be oriented at a trailing surface includedangle θ_(TS) with respect to the major surface 138. The trailing surfaceincluded angle θ_(TS) may be within a range from about 45° to about150°, such as from about 45° to about 60°, from about 60° to about 75°,from about 75° to about 90°, from about 90° to about 105°, from about105° to about 120°, from about 120° to about 120° and about 135°, orfrom about 135° to about 150°. In some embodiments, the trailing surfaceincluded angle θ_(TS) may be greater than the leading surface includedangle θ_(LS). Without being bound by any particular theory, it isbelieved that a trailing surface included angle θ_(TS) greater than aleading surface included angle θ_(LS) may facilitate increased supportof the asperity 130 by producing a so-called buttressing effect, supportthe asperity 130 from shear and normal forces, and facilitate increasedrigidity of the asperity 130 along the direction of motion.

In some embodiments, the trailing surface 144 may form a so-calledtrailing surface rake angle θ_(RTS) with the major surface 138. Thetrailing surface rake angle θ_(RTS) may be defined as an angle between aline normal to a major surface 138 of the wafer 102 and the trailingsurface 144. The trailing surface rake angle θ_(RTS) may be within arange from about 0° to about 60°, such as from about 0° to about 15°,from about 15° to about 30°, from about 30° to about 45°, or from about45° to about 60°. In some embodiments, the trailing surface rake angleθ_(RTS) may be within a range from about 15° to about 45°. The trailingsurface rake angle θ_(RTS) may also be referred to herein as thetrailing surface draft angle.

In some embodiments, one or more of the asperities 130 may exhibit aleading surface rake angle θ_(RLS) that is different from a trailingsurface rake angle θ_(RTS) of the respective one or more of theasperities 130. In some such embodiments, the asperities 130 may not besubstantially symmetrical. In other embodiments, one or more asperities130 may exhibit a leading surface rake angle θ_(RLS) that is the same asa trailing surface rake angle θ_(RTS) of the respective one or moreasperities 130.

Although FIG. 2C illustrates that the asperities 130 have a negativeleading surface rake angle θ_(RLS) (the leading surface included angleθ_(LS) is greater than about 90°), the disclosure is not so limited. Inother embodiments, the leading surface rake angle θ_(RLS) may be apositive rake angle, wherein the leading surface included angle θ_(LS)is less than about 90°.

Without being bound by any particular theory, it is believed that theleading surface included angle θ_(LS) may be tailored to modifyinteractions between the pad 114 and the wafer 102. For example,decreasing the leading surface included angle θ_(LS) (forming theleading surface included angle θ_(LS) to be more acute) may decrease anapplied force to remove material from the wafer 102. In other words, alower force may be required to be applied between the pad 114 and thewafer 102 to remove a given amount of material from the wafer 102. Insome embodiments increasing the leading surface included angle θ_(LS)(forming the leading surface included angle θ_(LS) to be less acute) mayincrease a durability of the leading surface 142 of the asperity 130.Similarly, increasing the trailing surface included angle θ_(TS) mayincrease a rigidity of the asperity 130. It is believed that highertrailing surface included angles θ_(TS) provide improved support for theasperity 130 in the form of a buttress, since the base of the asperity130 may have a greater dimension than the upper surface 140. Increasingthe leading surface included angle θ_(LS) may increase an applied forcebetween the leading surface 142 and the wafer 102, increasing frictionbetween the leading surface 142 and the wafer 102, and facilitate areduced surface roughness of the wafer 102 surface during a CMP process.

With reference to FIG. 2B and FIG. 2C, the skew angle α may be tailoredto adjust the shearing action on the wafer 102 imposed by the asperities130. As the skew angle α is increased, the shearing edge 146 of theasperity 130 may act on a smaller portion (surface area, swath) of thewafer 102. In addition, as the skew angle α is increased, the asperities130 may act with increased stiffness (since not as much of a surfacearea of the asperities 130 is orthogonal to the direction of motion ofthe wafer 102 in use and operation, which may also be referred to as aso-called buttressing effect). In addition, increasing the skew angle αmay increase an effective leading surface included angle θ_(LS)presented to the wafer 102 surface by the shearing edge 146. For caseswhere the leading surface included angle θ_(LS) is greater than about90°, the effective leading surface included angle θ_(LS) will appear toincrease due to the relative motion of the pad 114 and the wafer 102 andthe reduced swath of the wafer 102 contacted by the shearing edge 146,which may improve surface finish of the wafer 102 (i.e., reduce asurface roughness of the wafer 102 surface). Higher skew angles α mayalso direct more of the forces between the asperity 130 and the wafer102 in a radial direction, which may facilitate a shearing (cutting)action. As the skew angle α is decreased, the effective surface area(swath) of the wafer 102 acted upon by the shearing edge 146 of theasperity 130 may be larger, which may change an applied unit force ofthe shearing action imposed by the shearing edge 146 of the asperities130. In embodiments where the leading surface included angle θ_(LS) isless than 90°, the effective angle presented by the shearing edge 146 isdeceased, making it functionally more acute and reducing the shearingaction of the shearing edge 146 is reduced. In addition, as the skewangle α is decreased, the asperities 130 may exhibit a reduced stiffnessin use and operation, since the force exerted upon the asperities 130 ismore normal the longitudinal axes 134 of the asperities 130.

Although FIG. 2C illustrates the asperities 130 as comprising a separatematerial relative to the pad 114, the disclosure is not so limited. Insome embodiments, the asperities 130 are integral with the pad 114 andcomprise the same material composition as the pad 114.

Although FIG. 2C has been described and illustrated as includingasperities 130, each exhibiting a same leading surface included angleθ_(LS) as the leading surface included angle θ_(LS) as the otherasperities 130, the disclosure is not so limited. In other embodiments,at least some of the asperities 130 may have a different leading surfaceincluded angle θ_(LS) than other asperities 130 of the pad 114. As onlyone example, asperities 130 within a segment 114 a-114 h may have adifferent leading surface included angle θ_(LS) than other asperities130 within the same segment 114 a-114 h. In other embodiments, at leastone of the segments 114 a-114 h may include asperities 130 having aboutthe same leading surface included angle θ_(LS) as other asperities 130within the at least one of the segments 114 a-114 h and different thanthe leading surface included angle θ_(LS) as asperities 130 of at leastanother of the segments 114 a-114 h. For example, with reference to FIG.2D, the pad 114 may include a first asperity 130 a having a firstleading surface included angle θ_(LSa), a second asperity 130 b having asecond leading surface included angle θ_(LSb) different than the firstleading surface included angle θ_(LSa), and a third asperity 130 chaving a third leading surface included angle θ_(LSc) different than thefirst leading surface included angle θ_(LSa) and the second leadingsurface included angle θ_(LSb). In some embodiments, the trailingsurface included angle θ_(TS) of each asperity 130 a, 130 b, 130 c maybe substantially the same, even though the leading surface includedangles θ_(LS) may vary. In some such embodiments, the asperities 130 a,130 b, 130 c may be asymmetric.

Similarly, although FIG. 2C has been described and illustrated asincluding asperities 130, each exhibiting a same trailing surfaceincluded angle θ_(TS) as the trailing surface included angle θ_(TS) asthe other asperities 130, the disclosure is not so limited. In otherembodiments, at least some of the asperities 130 may have a differenttrailing surface included angle θ_(TS) than other asperities 130 of thepad 114. For example, in some embodiments, the first asperity 130 a mayhave a different trailing surface included angle θ_(TS) than the secondasperity 130 b and the third asperity 130 c, and the second asperity 130b may have a different trailing surface included angle θ_(TS) than thethird asperity 130 c.

In some embodiments, the upper surface 140 of the asperities 130 may notbe substantially parallel to the major surface 138. With reference toFIG. 2E, at least one asperity 130 may include an upper surface 140 thatis oriented at a relief angle θ_(R) with respect to major surface 138.In some embodiments, all of the asperities 130 include an upper surface140 that is oriented at the relief angle θ_(R) with respect to the majorsurface 138.

The relief angle θ_(R) may be tailored to modify an extent ofinteraction between the shearing edges 146 and upper surfaces 140 of theasperities 130, the wafer 102, and particles that may be present in thefluid medium 126 (FIG. 1). A relief angle θ_(R) larger than about 0° mayfacilitate removal of fluid medium 126, debris, or other materials froman interface between the asperities 130 and the wafer 102 during use andoperation. In addition, the relief angle θ_(R) may facilitate a shearingaction by increasing applied unit force between the shearing edge 146and the wafer 102. In other words, an increasing relief angle θ_(R) mayincrease force of interaction between the shearing edge 146 of theasperity 130 and the wafer 102.

As the relief angle θ_(R) is reduced (e.g., down to about 0°, whereinthe upper surface 140 is coplanar with the major surface 138 and thewafer 102), interactions between the upper surface 140 and the wafer 102are increased and applied unit force is decreased, as surface areabetween such an asperity 130 is increased. In addition, interactions inthe form of rubbing between particles in the fluid medium 126 (FIG. 1),the wafer 102, and the upper surface 140 may be increased relative toembodiments including a relief angle θ_(R) greater than about 0°. Thus,the relief angle θ_(R) may affect removal rates and planarization of thewafer 102 during use and operation.

The relief angle θ_(R) may be within a range from about 0° (greater thanabout 0°) to about 20° (e.g., less than about 20°), such as from about0° to about 2°, from about 2° to about 5°, from about 5° to about 10°,from about 10° to about 15°, or from about 15° to about 20°. In someembodiments, the relief angle is within a range from about 0° (greaterthan about 0°) to about 10° (e.g., less than about 10°). Although theasperities 130 of FIG. 2E have been described and illustrated to includea relief angle θ_(R) such that the shearing edge 146 is located higher(farther from the major surface 138) than other portions of the uppersurface 140, the disclosure is not so limited. In other embodiments, theasperities 130 may include a shearing edge 146 that is lower than otherportions of the upper surface 140.

Referring to FIG. 2F, in some embodiments, at least some of theasperities 130 may include an upper surface 140 oriented at a reliefangle θ_(R) and at least other asperities 130 may not include a reliefangle θ_(R) and may have an upper surface 140 that is substantiallyparallel with the major surface 138. In such embodiments, and as shownin FIG. 2F, a rotationally trailing asperity 130 may exhibit a lesserheight above major surface 138 than a rotationally leading asperity 130.In some embodiments, a rotationally leading asperity 130 may include arelief angle θ_(R) and a rotationally trailing asperity 130 may notinclude a relief angle θ_(R). In some such embodiments, the rotationallyleading asperity 130 may shear a portion of the wafer 102 to beplanarized while the rotationally trailing asperity 130 polishes thesurface of the wafer 102 by a polishing action or interaction withparticles of the fluid medium 126 particles, the wafer 102, and theupper surface 140 of the rotationally trailing asperity 130. In suchembodiments, rotationally trailing asperity 130 may serve as a standoffto limit the degree of penetration of shearing edge 146 into thematerial of wafer 102, thus enhancing planarity of the wafer 102surface.

With reference to FIG. 2G, in other embodiments, rotationally leadingasperity 130 may have an upper surface 140 that is substantiallyparallel with the major surface 138, while rotationally trailingasperity 130 may be positioned at a relief angle θ_(R). In such aninstance, the rotationally leading asperity 130 may clear particulatematter of the fluid medium as well as wafer debris, enabling shearingedge 146 of rotationally trailing asperity to more effectively engagematerial on the surface of wafer 102. Of course, if rotationally leadingasperity 130 is of lesser height than rotationally trailing asperity130, rotationally leading asperity may function to limit the depth ofengagement of shearing edge 146 of rotationally trailing asperity 130.In all such instances as illustrated and discussed with respect to FIG.2F and FIG. 2G, the presence of asperities with upper surfaces 140parallel to major surface 138 will serve to limit the unit force appliedby pad 114 to wafer 102.

In some embodiments, every other asperity 130 at the same radialdistance on the pad 114 (distance from the center of the pad 114) mayinclude a relief angle θ_(R) while the other asperities 130 do notinclude a relief angle θ_(R).

With reference to FIG. 2H, in some embodiments, the pad 114 includesasperities 130 having an upper surface 140 including a first portion 140a (e.g., a first segment, a first region) that is substantially planarwith the major surface 138 and a second portion 140 b (e.g., a secondsegment, a second region) that is oriented at the relief angle θ_(R)with respect to the major surface 138. In some such embodiments, thefirst portion 140 a of the asperity 130 may exhibit improved durabilityin use and operation relative to asperities 130 that do not include thefirst portion 140 a and the second portion 140 b. In some embodiments,the asperities 130 include second portions 140 b having the same reliefangle θ_(R). In other embodiments, at least some of the asperities 130may have a different relief angle θ_(R) than at least others of theasperities 130.

Although FIG. 2A through FIG. 2H have illustrated and described theasperities 130 as having a linear shape and a trapezoidal cross-section,the disclosure is not so limited. In other embodiments, a shape of theasperities 130 may be at least one of cylindrical, spherical (truncatedspherical), cubic, rectangular prism, triangular prism, hexagonal prism,triangular pyramid, 4, 5, or 6-sided pyramid, truncated pyramid, cone,truncated cone, arc shape, or another shape.

In some embodiments, one or more features of the pad 114 may change as afunction of radius (with a distance from the center of the pad 114). Forexample, one or more of the height H, width W, length L, skew angle α,leading surface included angle θ_(LS), trailing surface included angleθ_(TS), relief angle θ_(R), asperity 130 density, ratio between asperitylength L and asperity width W, or other parameter may change as afunction of radius (distance from a center of the pad 114). By way ofnonlimiting example, in some embodiments, an asperity length L maychange (increase, decrease) with an increasing distance from the centerof the pad 114. In other embodiments, the skew angle α may change(decrease, increase) with an increasing distance from the center of thepad 114. As another example, the leading surface included angle θ_(LS)may change (increase, decrease) with an increasing distance from thecenter of the polishing pad 114. In some embodiments, the leadingsurface included angle θ_(LS) and the trailing surface included angleθ_(TS) may change (increase, decrease) with an increasing distance fromthe center of the pad 114. In some embodiments, the relief angle θ_(R)may change (increase, decrease) with an increasing distance from thecenter of the pad 114. In yet other embodiments, the ratio between thelength and the width may change (increase, decrease) with an increasingdistance from the center of the pad 114. In some embodiments, the skewangle α may change (increase, decrease) with an increasing distance fromthe center of the pad 114.

A removal rate achieved by the pads 114 described herein may be within arange from about 100 Å/min to about 10,000 Å/min, such as from about 100Å/min to about 500 Å/min, from about 500 Å/min to about 1,000 Å/min,from about 1,000 Å/min to about 2,000 Å/min, from about 2,000 Å/min toabout 3,000 Å/min, from about 3,000 Å/min to about 4,000 Å/min, fromabout 4,000 Å/min to about 5,000 Å/min, or from about 5,000 Å/min toabout 10,000 Å/min. Although particular removal rates have beendescribed, the disclosure is not so limited and the removal rateachieved by the pads 114 may be different than those described.

In some embodiments, the pad 114 may be formed by a method that mayfacilitate fabrication of a pad 114 having uniformly sized, shaped, andpatterned features (e.g., asperities 130 and pores 136). By way ofnonlimiting example, the pad 114 may be formed by microreplication. Insome such embodiments, the pad 114 may be formed to include preciselyshaped topographical features (e.g., asperities 130 and pores 136) bycasting or molding a polymer (or a polymer precursor that is later curedto form a polymer) in a production tool, such as a mold. The mold mayinclude a plurality of topographical features that correspond to theasperities 130. In other embodiments, the pad 114 may be formed by, forexample, 3D printing techniques (e.g., stereolithography,photolithography, other 3D printing methods), embossing (e.g.,micro-embossing), or other methods, to form the precisely shaped andoriented asperities 130. In some such embodiments, the pad 114 may beformed to include asperities 130 that are formed to a net shape.Further, in some such embodiments, asperities 130 may be formed of adifferent material than the body of pad 114 and exhibit at least one ofdifferent hardness, stiffness, or density. In addition, differentformulations of the same material, for example polyurethane, may beemployed to form asperities 130 in comparison to the remainder of pad114.

Since the pad 114 is formed by microreplication or other methods, thepad 114 may be formed to include precisely patterned asperities 130having, for example, a desired skew angle α. In addition, the asperities130 may be precisely patterned to have controllable sizes and shapes(e.g., height H, length L, width W, leading surface rake angle θ_(RLS),trailing surface rake angle θ_(RTS), relief angle θ_(R)). By way ofcomparison, pads 114 formed by conventional techniques such as foamingpolyurethane may include asperities that are generated via porosity anddiamond disk conditioning, which may form asperities that do not exhibitsubstantially uniform sizes, shapes, and orientations.

Without being bound by any particular theory, it is believed that thepads 114 including the asperities 130 having the leading surface 142,the trailing surface 144, the shearing edge 146, the relief angle θ_(R),the leading surface included angle θ_(LS), the trailing surface includedangle θ_(TS), the height H, the width W, and the length L, and otherfeatures as described herein, may facilitate improved planarization,controllability, and repeatability of the CMP process. In someembodiments, a length scale of planarization (e.g., ability of the pad114 to planarize features having a desired pitch) may be tailored by theasperities 130. For example, the length L of the asperities 130 mayfacilitate bridging of high points of wafer topography, facilitatingremoval of material from the high points while reducing material removalfrom the low points of wafer topography. In addition to the length L ofthe asperities 130, adjusting the ratio of the length L to the width Wmay affect the planarization length scale. In addition, the radial pitchP_(R) and the transverse pitch P_(T) may be tailored to adjust theradial overlap and the transverse overlap of adjacent asperities 130,which in turn, may affect a length scale of planarization (e.g.,increasing one or both of the radial pitch P_(R) and the transversepitch P_(T) may increase the planarization length scale of the pad 114).In some embodiments, the skew angle α may be altered to alter the lengthof the asperity 130 in the transverse direction and in the radialdirection.

In some embodiments, a gel-like hydrolyzed layer of fluid medium andmaterials removed from the wafer 102 may be more effectively removedfrom the interface between the wafer 102 and the pad 114 due to thesizes, shapes, and orientations of the asperities 130 along the surfaceof the pad 114. The asperities 130 may be designed and oriented alongthe surface of the pad 114 to facilitate shearing and a scraping(cutting) action to the surface of the wafer 102, as opposed to only apolishing action, as in conventional CMP pads. In other words, theshearing edges 146 of leading surfaces 142 of the asperities 130 may beoriented, sized, and shaped to remove material from the surface of thewafer 102 by shearing action. Even though the fluid medium 126 may forma hydrolyzed gel-like layer including siloxane linkages (—Si—O—Si—)between surfaces of the wafer 102 and the fluid medium 126 particles,the asperities 130 may be sized, shaped, and oriented to remove thehydrolyzed layer.

The pads 114 described herein may facilitate improved uniformity ofplanarization relative to conventional polishing pads. The pads 114 mayexhibit a reduced within wafer non-uniformity and a reduced wafer towafer non-uniformity relative to conventional polishing pads. The pad114 described herein may be used in stop-in-film CMP processes,stop-on-film applications, and buffing applications wherein surfacetopography and surface roughness is removed from a wafer. The pads 114may be used in CMP processes including planarization of metals such asat least one of tungsten, titanium, nickel, platinum, ruthenium,rhodium, aluminum, copper, molybdenum, gold, iridium, metal oxides suchas titanium oxide, hafnium oxide, zirconium oxide, aluminum oxide,tungsten oxide, ruthenium oxide, iridium oxide, metal nitrides such astungsten nitride, titanium nitride, tantalum nitride, titanium aluminumnitride, dielectric materials such as silicon dioxide, phosphosilicateglass, borosilicate glass, fluorosilicate glass, metal silicides, metalcarbides, a conductively-doped semiconductor material (e.g.,conductively-doped silicon, conductively-doped germanium,conductively-doped silicon germanium), polysilicon, a polymeric filmsuch as a photoresist material, or another material.

Although the pads 114 of FIG. 2A through FIG. 2H have been described ascomprising segments 114 a-114 h having a particular size, shape, andorientation, and having grooves 145 having a particular pattern, thedisclosure is no so limited. In some embodiments, the grooves 145 mayexhibit at least one of a circular shape (e.g., the pad 114 may includeconcentric grooves), a spiral shape, or may extend in the radialdirection. For example, with reference to FIG. 3, a pad 314 may includesegments 314 a-314 h, each including an outer first portion 315 a, aninner third portion 315 c, and a middle second portion 315 b between thefirst portion 315 a and the second portion 315 b. The pad 314 mayinclude asperities 130, as described above with reference to FIG. 2Athrough FIG. 2H, but are not illustrated in FIG. 3 for clarity.

In some embodiments, the pad 314 may include grooves 345 forfacilitating removal of materials removed from the wafer 102 from theinterface between the pad 314 and the wafer 102. In addition, thegrooves 345 may facilitate flow of fluid medium 126 (FIG. 1) to variouslocations on the pad 314 surface. In some embodiments, the grooves 345may be located between adjacent segments 314 a-314 h. In addition, thegrooves 345 may be located between the portions of each segment 314a-314 c, such as between the first portion 315 a and the second portion315 b and between the second portion 315 b and the third portion 315 c.The grooves 345 may form a pattern of concentric circles (correspondingto the first portions 315 a, the second portions 315 b, and the thirdportions 315 c).

Referring to FIG. 4, a pad 414 may include segments 414 a-414 h having adifferent design that that illustrated in FIG. 3. For example, the pad414 may include segments 414 a-414 h, each having an outer first portion415 a and an inner second portion 415 b. The pad 414 may include grooves445, which may be located at boundaries between the segments 414 a-414 hand between portions of each segment 414 a-414 h. For example, grooves445 may be located between the first portion 415 a and the secondportion 415 b. The grooves 445 between the first portion 415 a and thesecond portion 415 b may be substantially linear.

FIG. 5 illustrates a pad 514 including segments 514 a-514 h and havinggrooves 545 between the segments 514 a-514 h. The segments 514 a-514 hmay comprise arcuate (spiraling) sides. The pad 514 may include grooves545 located at the boundary between adjacent segments 514 a-514 h. Thus,the grooves 545 may exhibit a spiral shape having an arcuate patternfrom a circumference of the pad 514 to the center of the pad 514.

FIG. 6 illustrates a pad 614 including segments 614 a-614 h and havinggrooves 545 between the segments 614 a-614 h. The segments 614 a-614 hmay comprise arcuate (spiraling) sides. The pad 614 may include grooves645 located at the boundary between adjacent segments 614 a-614 h. Thus,the grooves 645 may exhibit a spiral shape having an arcuate patternfrom a circumference of the pad 614 to the center of the pad 614.

Thus, in accordance with embodiments of the disclosure, a pad forchemical mechanical planarization comprises a material having a majorsurface, and asperities extending from the major surface, a ratiobetween a length and a width of each of the asperities greater thanabout 2:1, and an included angle between a leading surface of at leastsome asperities and the major surface greater than about 90°.

Furthermore, in accordance with additional embodiments of thedisclosure, a pad comprises a substantially circular base having a majorsurface, and asperities extending a height above the major surface. Atleast some of the asperities individually comprise sides defining aleading surface and a trailing surface, and an upper surface between theleading surface and the trailing surface, wherein an angle between themajor surface and the upper surface is within a range from greater thanabout 0° to about 20°.

Moreover, in accordance with embodiments of the disclosure, a tool forchemical mechanical planarization comprises a wafer carrier configuredto hold a wafer, a platen, and a pad coupled to the platen. The padcomprises a material having a major surface, and asperities extendingabove the major surface by a height, at least some of the asperitieseach having a width and a length, wherein a longitudinal axis of the atleast some of the asperities is oriented at an angle with respect to alongitudinal axis of at least some other of the asperities.

In addition, in accordance with embodiments of the disclosure, a pad forchemical mechanical planarization comprises a material having a majorsurface, and asperities on the major surface, the asperities comprisinga leading surface, a trailing surface, an upper surface between theleading surface and the trailing surface, a shearing edge at anintersection of the leading surface and the upper surface.

Furthermore, in accordance with additional embodiments of thedisclosure, a pad comprises at least one rotationally leading asperityover a major surface of a base material and a rotationally trailingasperity rotationally trailing the at least one rotationally leadingasperity. The at least one rotationally leading asperity comprises aleading surface, a trailing surface, and an upper surface between theleading surface and the trailing surface, the upper surface being angledwith respect to the major surface.

In addition, in accordance with embodiments of the disclosure, a methodof planarizing a semiconductor device comprises placing a wafer in awafer carrier, and contacting the wafer with a pad while moving thewafer relative to the pad. The pad comprises segments defining at leasta portion of the pad, at least some of the segments exhibitingasperities each individually having a width and a length, an anglebetween a longitudinal axis of each of the asperities of a first segmentand a line orthogonal to a tangent of the pad at the first segmentdifferent than another angle between an additional longitudinal axis ofeach of the asperities of a second segment and a line orthogonal toanother tangent of the pad at the second segment. The method furthercomprises shearing material from a surface of the wafer in contact withat least some of the asperities having a shearing edge at a distal endof the asperities of the at least some of the asperities.

Additional nonlimiting example embodiments of the disclosure aredescribed below.

Embodiment 1: A pad for chemical mechanical planarization, the polishingpad comprising: a material having a major surface; and asperitiesextending from the major surface, a ratio between a length and a widthof each of the asperities greater than about 2:1, and an included anglebetween a leading surface of at least some asperities and the majorsurface greater than about 90°.

Embodiment 2: The pad of Embodiment 1, wherein the included anglebetween the leading surface of the at least some asperities is within arange from about 90° to about 120°.

Embodiment 3: The pad of Embodiment 1 or Embodiment 2, wherein anotherincluded angle between a trailing surface of the at least someasperities and the major surface is greater than about 90°.

Embodiment 4: The pad of Embodiment 3, wherein the included anglebetween the leading surface of the at least some asperities and themajor surface is different than the another included angle between thetrailing surface of the at least some asperities and the major surface.

Embodiment 5: The pad of any one of Embodiments 1 through 4, wherein theat least some asperities are asymmetrical.

Embodiment 6: The pad of any one of Embodiments 1 through 5, wherein theat least some asperities comprise an upper surface oriented at a reliefangle relative to the major surface.

Embodiment 7: The pad of Embodiment 6, wherein the relief angle isgreater than 0° and less than or equal to about 20°.

Embodiment 8: The pad of any one of Embodiments 1 through 7, wherein atleast some other of the asperities comprise an upper surfacesubstantially parallel with the major surface of the base material.

Embodiment 9: The pad of any one of Embodiments 1 through 8, wherein theratio between the length and the width of each of the asperities isgreater than about 5:1.

Embodiment 10: The pad of any one of Embodiments 1 through 9, whereinthe pad is substantially circular and a distance between asperities in aradial direction is within a range from about 0.5 μm to about 1,000 μm.

Embodiment 11: The pad of any one of Embodiments 1 through 10, whereinthe pad is substantially circular and the asperities are oriented tohave a skew angle between a longitudinal axis of the asperities and aline perpendicular to a tangent of the polishing pad proximate theasperities, the skew angle within a range from about 25° and about 45°.

Embodiment 12: The pad of any one of Embodiments 1 through 11, whereinthe skew angle of the at least some asperities varies with a distancefrom a center of the pad.

Embodiment 13: The pad of any one of Embodiments 1 through 12, whereinthe pad is substantially circular and substantially all of theasperities are oriented at about a same angle relative to a lineperpendicular to a tangent of the pad proximate a location of respectiveasperities.

Embodiment 14: A pad, comprising: a substantially circular base having amajor surface; and asperities extending a height above the majorsurface, at least some of the asperities individually comprising: sidesdefining a leading surface and a trailing surface; and an upper surfacebetween the leading surface and the trailing surface, wherein an anglebetween the major surface and the upper surface is within a range fromgreater than about 0° to about 20°.

Embodiment 15: The pad of Embodiment 14, wherein the angle is greaterthan 0° and less than or equal to about 10°.

Embodiment 16: The pad of Embodiment 14 or Embodiment 15, wherein the atleast some of the asperities each exhibit a substantially linear shape.

Embodiment 17: The pad of any one of Embodiments 14 through 16, whereinthe at least some of the asperities have a length being greater than awidth of the respective asperities of the at least some of theasperities.

Embodiment 18: The pad of any one of Embodiments 14 through 17, whereinthe at least some of the asperities are oriented on the pad such that alongitudinal axis of the at least some of the asperities is notsubstantially parallel with a longitudinal axis of at least some otherof the asperities.

Embodiment 19: The pad of any one of Embodiments 14 through 18, whereina skew angle between a longitudinal axis of the at least some of theasperities and a line orthogonal to a tangent of the pad proximate eachrespective asperity is substantially the same.

Embodiment 20: The pad of Embodiment 19, wherein the skew angle isgreater than 0° and less than or equal to about 60°.

Embodiment 21: The pad of any one of Embodiments 14 through 20, whereinan angle between the leading surface and the major surface of the baseis different than an angle between the trailing surface and the majorsurface of the base.

Embodiment 22: The pad of any one of Embodiments 14 through 21, whereinthe at least some of the asperities are asymmetrical.

Embodiment 23: The pad of any one of Embodiments 14 through 22, whereinthe at least some of the asperities are asymmetrically arranged on thepolishing pad.

Embodiment 24: The pad of any one of Embodiments 14 through 23, whereinthe angle between the major surface of the base and the upper surfacevaries with a distance of the respective asperity from a center of thepad.

Embodiment 25: A tool for chemical mechanical planarization, the toolcomprising: a wafer carrier configured to hold a wafer; a platen; and apad coupled to the platen, the pad comprising: a material having a majorsurface; and asperities extending above the major surface by a height,at least some of the asperities each having a width and a length,wherein a longitudinal axis of the at least some of the asperities isoriented at an angle with respect to a longitudinal axis of at leastsome other of the asperities.

Embodiment 26: The tool of Embodiment 25, wherein a ratio between thelength and the width of the at least some of the asperities is greaterthan about 5:1.

Embodiment 27: The tool of Embodiment 25 or Embodiment 26, wherein anangle between a leading surface of the at least some of the asperitiesand the major surface of the material is greater than about 90°.

Embodiment 28: The tool of Embodiment 27, wherein an additional anglebetween a trailing surface of the at least some of the asperities andthe major surface of the material is greater than about 90° and isdifferent than the angle between the leading surface of the at leastsome of the asperities and the major surface of the material.

Embodiment 29: The tool of any one of Embodiments 25 through 28, whereinan upper surface of the at least some of the asperities is angled withrespect to the major surface.

Embodiment 30: The tool of any one of Embodiments 25 through 29, whereinthe at least some of the asperities comprise an upper surface having afirst portion being substantially parallel with the major surface and asecond portion being angled with respect to the major surface.

Embodiment 31: The tool of Embodiment 30, wherein a distance between thefirst portion of the upper surface and the major surface of the materialis greater than another distance between the second portion of the uppersurface and the major surface of the material.

Embodiment 32: The tool of Embodiment 30 or Embodiment 31, wherein thefirst portion of the upper surface is located proximate a leadingsurface of the at least some of the asperities and the second portion ofthe upper surface is located proximate a trailing surface of the atleast some of the asperities.

Embodiment 33: The tool of any one of Embodiments 25 through 32, whereinthe pad comprises pores extending below the major surface of thematerial.

Embodiment 34: The tool of any one of Embodiments 25 through 33, whereinthe at least some of the asperities comprise an upper surface forming anangle with respect to the major surface and the at least others of theasperities comprise an upper surface that is substantially parallel withthe major surface.

Embodiment 35: A method of planarizing a semiconductor device, themethod comprising: contacting a wafer with a pad while moving the waferrelative to the pad, the pad comprising: segments defining at least aportion of the pad, at least some of the segments exhibiting asperitieseach individually having a width and a length, an angle between alongitudinal axis of each of the asperities of a first segment and aline orthogonal to a tangent of the pad at the first segment differentthan another angle between an additional longitudinal axis of each ofthe asperities of a second segment and a line orthogonal to anothertangent of the pad at the second segment; and shearing material from asurface of the wafer in contact with at least some of the asperitieshaving a shearing edge at a distal end of the asperities of the at leastsome of the asperities.

Embodiment 36: The method of Embodiment 35, wherein moving the waferwith relative to the pad comprises independently rotating each of thewafer and the pad.

Embodiment 37: The method of Embodiment 35 or Embodiment 36, whereincontacting the wafer with a pad comprises contacting the wafer with apad comprising at least eight segments.

Embodiment 38: The method of any one of Embodiments 35 through 37,further comprising introducing a fluid medium between the wafer and thepad while contacting the wafer with the pad.

Embodiment 39: The method of Embodiment 38, wherein introducing a fluidmedium between the wafer and the pad comprises introducing deionizedwater between the wafer and the pad.

Embodiment 40: A pad for chemical mechanical planarization, the padcomprising: a material having a major surface; and asperities on themajor surface, the asperities comprising a leading surface, a trailingsurface, an upper surface between the leading surface and the trailingsurface, a shearing edge at an intersection of the leading surface andthe upper surface.

Embodiment 41: The pad of Embodiment 40, wherein an angle between themajor surface and the leading surface is different than an angle betweenthe major surface and the trailing surface.

Embodiment 42: The pad of Embodiment 40 or Embodiment 41, wherein theupper surface is not parallel with the major surface.

Embodiment 43: The pad of any one of Embodiments 40 through 42, whereinthe upper surface is oriented at an angle within a range from greaterthan about 0° to about 10° with respect to the major surface.

Embodiment 44: The pad of any one of Embodiments 40 through 43, furthercomprising at least some pores located between adjacent asperities.

Embodiment 45: The pad of any one of Embodiments 40 through 44, whereinthe pad comprises at least eight segments, the asperities of eachsegment parallel with other asperities of their respective segment andangled with respect to asperities of at least other segments.

Embodiment 46: A pad, comprising: at least one rotationally leadingasperity over a major surface of a base material, wherein the at leastone rotationally leading asperity comprises: a leading surface; atrailing surface; and an upper surface between the leading surface andthe trailing surface; and a rotationally trailing asperity rotationallytrailing the at least one rotationally leading asperity, at least one ofthe upper surface of the rotationally leading asperity and an uppersurface of the rotationally trailing asperity being angled with respectto the major surface.

Embodiment 47: The pad of Embodiment 46, further comprising a shearingedge at an intersection of the leading surface and the upper surface.

Embodiment 48: The pad of Embodiment 45 or Embodiment 46, wherein therotationally trailing asperity has a height less than a height of therotationally leading asperity.

Embodiment 49: The pad of any one of Embodiments 45 through 48, whereinthe upper surface of the rotationally trailing asperity is parallel withthe major surface.

Embodiment 50: The pad of any one of Embodiments 45 through 48, whereinthe upper surface of the rotationally leading asperity is parallel withthe major surface and the upper surface of the rotationally trailingasperity is oriented at an angle with respect to the major surface.

While certain illustrative embodiments have been described in connectionwith the figures, those of ordinary skill in the art will recognize andappreciate that embodiments encompassed by the disclosure are notlimited to those embodiments explicitly shown and described herein.Rather, many additions, deletions, and modifications to the embodimentsdescribed herein may be made without departing from the scope ofembodiments encompassed by the disclosure, such as those hereinafterclaimed, including legal equivalents. In addition, features from onedisclosed embodiment may be combined with features of another disclosedembodiment while still being encompassed within the scope of thedisclosure.

What is claimed is:
 1. A chemical mechanical planarization tool,comprising: a pad comprising a major surface; a first group ofasperities extending from the major surface of the pad, the asperitiesof the first group of asperities comprising: side surfaces extendingfrom the major surface of the pad; and an upper surface spanning betweenthe side surfaces, at least a portion of the upper surface parallel tothe major surface of the pad; and a second group of asperities extendingfrom the major surface of the pad, the asperities of the second group ofasperities comprising: additional side surfaces extending from the majorsurface of the pad; and an additional upper surface spanning between theadditional side surfaces, the additional upper surface oriented at anangle with respect to the major surface of the pad.
 2. The chemicalmechanical planarization tool of claim 1, wherein the upper surface ofone or more of the asperities of the first group of asperities comprisesan additional portion extending from the at least a portion of the uppersurface to one of the side surfaces of the one or more asperities of thefirst group of asperities, the additional portion oriented at anadditional angle with respect to the major surface of the pad.
 3. Thechemical mechanical planarization tool of claim 2, wherein a distancebetween the major surface and the at least a portion of the uppersurface parallel to the major surface of the pad is greater than anotherdistance between the additional portion and the major surface of thepad.
 4. The chemical mechanical planarization tool of claim 2, wherein:the at least a portion of the upper surface parallel to the majorsurface is located proximate a leading surface of the one or moreasperities of the first group of asperities; and the additional portionis located proximate a trailing surface of the one or more asperities ofthe first group of asperities.
 5. The chemical mechanical planarizationtool of claim 1, wherein: one or more asperities of the second group ofasperities comprises a rotationally leading asperity; and one or moreasperities of the first group of asperities comprises a rotationallytrailing asperity located rotationally behind the rotationally leadingasperity.
 6. The chemical mechanical planarization tool of claim 5,wherein the additional upper surface of the rotationally leadingasperity is farther from the major surface than the upper surface of therotationally trailing asperity.
 7. The chemical mechanical planarizationtool of claim 1, wherein: one or more asperities of the first group ofasperities comprises a rotationally leading asperity; and one or moreasperities of the second group of asperities comprises a rotationallytrailing asperity located rotationally behind the rotationally leadingasperity.
 8. The chemical mechanical planarization tool of claim 7,wherein the upper surface of the rotationally leading asperity is closerto the major surface than the additional upper surface of therotationally trailing asperity.
 9. The chemical mechanical planarizationtool of claim 1, wherein asperities of the first group of asperitiesalternate with asperities of the second group of asperities in a radialdirection.
 10. A chemical mechanical planarization tool, comprising: acircular pad; and asperities extending from an upper surface of thecircular pad, the asperities arranged on the upper surface to overlapone another in a radial direction and in a direction transverse to theradial direction.
 11. The chemical mechanical planarization tool ofclaim 10, wherein one or more asperities of the asperities comprises: anincluded angle between a leading surface of the one or more asperitiesand the upper surface of the circular pad greater than about 90°; and atrailing surface included angle between a trailing surface of the one ormore asperities and the upper surface greater than about 90° anddifferent than the included angle.
 12. The chemical mechanicalplanarization tool of claim 11, wherein the trailing surface includedangle is greater than the included angle.
 13. The chemical mechanicalplanarization tool of claim 11, wherein one or more additionalasperities of the asperities comprises an additional included angledifferent than the included angle of the one or more asperities.
 14. Thechemical mechanical planarization tool of claim 13, wherein the one ormore additional asperities comprises a trailing surface included anglesubstantially the same as the trailing surface included angle of the oneor more asperities.
 15. The chemical mechanical planarization tool ofclaim 13, wherein the one or more additional asperities comprises atrailing surface included angle different than the trailing surfaceincluded angle of the one or more asperities.
 16. The chemicalmechanical planarization tool of claim 10, wherein a ratio of a pitch ofthe asperities in a direction transverse to the radial direction to apitch of the asperities in the radial direction is within a range fromabout 1.0:1.0 to about 2.5:1.0.
 17. The chemical mechanicalplanarization tool of claim 10, wherein a transverse pitch of theasperities in a direction transverse to the radial direction is greaterthan a radial pitch of the asperities in the radial direction.
 18. Thechemical mechanical planarization tool of claim 10, wherein theasperities each exhibit a length greater than a width thereof, alongitudinal axis of each asperity substantially parallel to alongitudinal axis of neighboring asperities and oriented at an anglewith respect to a longitudinal axis of distal asperities.
 19. A pad forchemical mechanical planarization, the pad comprising: a material havinga major surface; and asperities on the major surface, the asperitiescomprising a leading surface, a trailing surface, an upper surfacebetween the leading surface and the trailing surface, and a shearingedge at an intersection of the leading surface and the upper surface,one or more of an angle between the leading surface and the majorsurface, an angle between the trailing surface and the major surface, anangle between the upper surface and the major surface, and a skew angleof the asperities changing as a function of a distance from a center ofthe pad.
 20. The pad of claim 19, wherein the angle between the uppersurface and the major surface changes as a function of the distance fromthe center of the pad.